ackerman tech file

8/8/2019 Ackerman Tech File

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The simple spreadsheet format of this program imposes some limitations.

Some combinations of data will crash the program and, because you can only change one entry at a t

it is likely that unstable situations will occur when you try to make radical changes to the layout.

If the geometry is impractical - say the combined lengths of the steering arm and trackrod are too sho

(or too long) ever to fit - it will crash.

To do this, Click the Visual Basic Editor icon in the VB toolbar.

If it isn't shown, select View|Toolbars then click Visual Basic if it isn't already 'checked'.

Find the Visual Basic Editor icon by passing the cursor over the icons until the Tool Tip pops up to ide

Click on it to show the Editor screen.You will find that the program has stuck on the highlighted line.

Click on Run|Reset, then go back to the usual spreadsheet screen by clicking the 'XL' (Excel) icon,

usually found on the extreme left of the Toolbar, when the Editor is showing.

Follow the instructions given on the diagram screen to delete old lines.

Erase any remaining lines by clicking on them individually and pressing Delete.

After a crash, you will need to 'Reset' the Visual Basic for Applications (VBA) program that creates th

Another limitation is the inability automatically to update the diagram when new information is enter


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ime,

t,

ntify it.

e diagram.

d.


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Half Axle 25 inches

Half Rack 7

Steering Arm -3

Track Rod 20

Rack Back -8

Wheelbase 83

Static toe-in (per wheel) 0 degrees 0

Front tyre slip angle 10 degrees 0.17

Rear tyre slip angle 10 degrees 0.17

Steer arm angle (static) 25.4 degrees

Arm - rod angle (static) 79.9 degrees

Ackermann effect (static) 158 per cent

Positive (pulling on trackrod) Negative (pushing)

Rack Travel alpha cos term beta cos term tan term alpha cos ter beta cos term tan term

0 0.03 0.1750000 -0.44 0.03 -0.44

0.02 0.03 -0.44 0.02 -0.44

0.04 0.04 -0.45 0.01 -0.44

0.06 0.04 -0.45 0.01 -0.44

0.08 0.05 -0.45 0 -0.44

0.1 0.06 -0.45 -0.01 -0.44

0.2 0.09 -0.45 -0.04 -0.44

0.3 0.12 -0.45 -0.07 -0.44

0.4 0.15 -0.45 -0.1 -0.43

0.5 0.18 -0.46 -0.13 -0.43

0.6 0.21 -0.46 -0.16 -0.43

0.7 0.24 -0.46 -0.19 -0.43

0.8 0.27 -0.47 -0.22 -0.430.9 0.31 -0.47 -0.25 -0.42

1 0.34 -0.47 -0.27 -0.42

1.1 0.37 -0.47 -0.3 -0.42

1.2 0.4 -0.48 -0.33 -0.42

1.3 0.43 -0.48 -0.36 -0.41

1.4 0.47 -0.48 -0.39 -0.41

1.5 0.5 -0.48 -0.42 -0.41

1.6 0.53 -0.49 -0.45 -0.41

1.7 0.56 -0.49 -0.48 -0.41

1.8 0.6 -0.49 -0.51 -0.4

1.9 0.63 -0.5 -0.54 -0.4

2 0.66 -0.5 -0.56 -0.4

0 0.5 1 1.5-2.00

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

Rack travel (inches)

St

eerangl e

differenc

e

(degr

ees)

CL

half axle

half rack

steering arm

track rod

rack back

Schematic layout

steer arm angle

arm-rod angle

Draw turncentresondiagram


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ACOS term ATAN term Theta pull Theta pushMean Diff

88.55 -23.96 25.42 88.55 -23.96 25.42 0.0 0.0 0.0 0.0

88.19 -23.99 25.79 88.90 -23.94 25.04 0.4 0.4 0.4 0.0

87.84 -24.01 26.17 89.25 -23.92 24.67 0.7 0.7 0.7 0.0

87.49 -24.03 26.54 89.60 -23.89 24.30 1.1 1.1 1.1 0.0

87.14 -24.06 26.92 89.95 -23.87 23.92 1.5 1.5 1.5 0.0

86.79 -24.08 27.29 90.29 -23.84 23.55 1.9 1.9 1.9 0.0

85.02 -24.20 29.18 92.04 -23.73 21.69 3.8 3.7 3.7 0.0

83.24 -24.32 31.08 93.78 -23.61 19.84 5.7 5.6 5.6 0.1

81.45 -24.44 32.99 95.51 -23.50 17.99 7.6 7.4 7.5 0.1

79.65 -24.57 34.92 97.24 -23.39 16.14 9.5 9.3 9.4 0.2

77.82 -24.69 36.87 98.98 -23.27 14.29 11.5 11.1 11.3 0.3

75.98 -24.82 38.84 100.72 -23.16 12.45 13.4 13.0 13.2 0.5

74.11 -24.94 40.83 102.46 -23.05 10.60 15.4 14.8 15.1 0.672.22 -25.07 42.85 104.20 -22.94 8.74 17.4 16.7 17.1 0.8

70.30 -25.20 44.90 105.95 -22.83 6.88 19.5 18.5 19.0 0.9

68.35 -25.33 46.98 107.72 -22.73 5.01 21.6 20.4 21.0 1.2

66.36 -25.46 49.10 109.49 -22.62 3.13 23.7 22.3 23.0 1.4

64.34 -25.60 51.26 111.28 -22.51 1.24 25.8 24.2 25.0 1.7

62.27 -25.73 53.46 113.08 -22.41 -0.67 28.0 26.1 27.1 2.0

60.16 -25.87 55.71 114.90 -22.31 -2.60 30.3 28.0 29.2 2.3

57.99 -26.00 58.02 116.74 -22.20 -4.54 32.6 30.0 31.3 2.6

55.75 -26.14 60.39 118.61 -22.10 -6.51 35.0 31.9 33.4 3.0

53.45 -26.28 62.83 120.50 -22.00 -8.50 37.4 33.9 35.7 3.5

51.06 -26.42 65.36 122.43 -21.90 -10.53 39.9 35.9 37.9 4.0

48.59 -26.57 67.98 124.39 -21.80 -12.59 42.6 38.0 40.3 4.6

2 2.5

Column Q

Column AB

0-60.0

-40.0

-20.0

0.0

20.0

40.0

60.0

80.0

Actual wheel

Rack travel (inch

Steerangles

/radius


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25 22.5 Half Axle

7 14 Half Rack

-3 4 Steering Arm

20.5 7 Track Rod

-8 5 Rack Back

83 86 Wheelbase

0 0 Static toe-in (per whee

0 0 Front tyre slip angle

0 0 Rear tyre slip angle

These datasets can be copied and pasted to cel

to illustrate front and rear-mounted racks.

Diff/mean Turn Radius Langensperger beta acos term beta Arm-rod angle Theta right Radius ft

0.0 Infinite 0.00 79.9 56.0 79.9 0.0

-0.1 12710 0.00 -0.4 1059.20

0.2 6355 -0.01 -0.7 529.57

0.3 4236 -0.01 -1.1 353.01

0.4 3177 -0.02 -1.5 264.72

0.5 2541 -0.04 -1.9 211.74

1.0 1268 -0.15 -3.7 105.71

1.4 843 -0.33 -5.6 70.29

1.9 630 -0.59 -7.4 52.53

2.4 502 -0.92 -9.3 41.82

2.9 416 -1.33 -11.1 34.65

3.4 354 -1.81 -13.0 29.50

3.9 307 -2.36 -14.8 25.604.4 271 -2.99 -16.7 22.54

5.0 241 -3.69 -18.5 20.08

5.5 216 -4.47 -20.4 18.03

6.1 196 -5.32 -22.3 16.31

6.6 178 -6.25 -24.2 14.83

7.2 162 -7.24 -26.1 13.54

7.8 149 -8.31 -28.0 12.40

8.4 137 -9.45 -30.0 11.39

9.1 126 -10.66 -31.9 10.47

9.8 116 -11.93 -33.9 9.64

10.5 106 -13.27 -35.9 8.87

11.3 98 -14.67 -38.0 8.16

2

angles

Column N

Column X

Column Q

Column Y

Column AA

)


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l)

ls B1 to B9,

dius with slrn centre f Langenspemean-slip Radius Forward of front axle

-10.0

1028.44 2176.1 -0.04 -9.6 12341 2093

514.78 1089.2 -0.07 -9.3 6177 1006

343.55 726.9 -0.11 -8.9 4123 644

257.92 545.7 -0.14 -8.5 3095 463

206.53 437.0 -0.16 -8.1 2478 354

103.70 219.4 -0.25 -6.3 1244 136

69.35 146.7 -0.26 -4.4 832 64

52.13 110.3 -0.20 -2.5 626 27

41.75 88.3 -0.06 -0.6 501 5

34.79 73.6 0.15 1.3 417 -9

29.79 63.0 0.45 3.2 357 -20

26.01 55.0 0.82 5.1 312 -2823.05 48.8 1.27 7.1 277 -34

20.65 43.7 1.81 9.0 248 -39

18.67 39.5 2.42 11.0 224 -43

17.00 36.0 3.12 13.0 204 -47

15.56 32.9 3.90 15.0 187 -50

14.31 30.3 4.76 17.1 172 -53

13.21 27.9 5.71 19.2 159 -55

12.22 25.9 6.74 21.3 147 -57

11.34 24.0 7.86 23.4 136 -59

10.53 22.3 9.07 25.7 126 -61

9.79 20.7 10.35 27.9 117 -62

9.10 19.2 11.73 30.3 109 -64


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Half plan view of steering geometry If you want to display the turn centres, checAckermann 158 percent Scale OK

You have to erase the drawings manuallyClick on the arrow near the 'Draw' in lower left corner.

Left click and drag a box to enclose all the lines making up the drawing.

Release to close the box. Press 'Del' to erase the lines.Click on the 'Draw' arrow to cancel it.

A new drawing will be done when you enter new data into the spreadsheet.

This procedure is necessary because Microsoft appears not to include automatic facilities for redrawing in the VBA languag

Blue crosses show turn centre at indicated rack travel and turn radius


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k the box on the 'Data' sheet.

built into Excel.


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ackerman tech file

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